How to repair a cracked or chipped windshield

Windshield chip repair

Chipped windshields are just a part of life when living in Alberta. Due to the gravel salts the province uses on snowy, icy roads in the fall, winter and spring, it’s only a matter of time before you get a chip on your windshield. Do you know anyone without a chipped windshield? It’s hard to come by a windshield that’s not chipped, particularly in the spring after a long winter.  It’s especially frustrating if it’s on your brand new vehicle.

With the temperature differential between the outside and the inside defrost heater, it’s not long before that chip develops into a crack.  Of course, it seems like these cracks and chips always end up in your line of sight, obstructing your view of the road.  This can turn into a hazard particularly if your crack is deep enough that moisture gets in and causes it to fog on the inside or middle of the pane. 

The first thing you should do is to have a very close look at that chip through a magnifying glass.  What does it look like?

What types of cracks can I repair?

Any chip that goes to the surface of the glass at a perpendicular angle or shallow angle can be filled.  This is basically any chip that hasn’t flaked a big piece of glass off, and includes chips that are cone shaped and leaf shaped. 


Many types of chips can be repaired with adhesive injection, but some damage is beyond replacement and does call for total windshield replacement. Image source: Popular Mechanics.

One of the best options is to inject an epoxy or acrylic adhesive filler into the chip. The best you can hope for is to fill in most of the chip, though keep in mind it may still leave a visible flaw. However, this is better than leaving the chip to spread to a long crack, which sometimes isn’t repairable.  But the improvement will be dramatic, and even though you still may be able to see it, it won’t spread across the windshield. 

Make sure to fix it as soon as possible from the time it gets damaged. Dirt and debris will collect inside the chip or crack, and is hard to clean out.

Repair or Replace?

Most of the time, your windshield can just be repaired instead of replaced. This is much cheaper, and if done professionally you can expect to pay around $30 or more depending on the number of cracks or repairs that need to be done. If in doubt, the glass service advisor will be able to give you advice if you should repair or replace your windshield based on the severity of the damage.

To understand if you need to repair or replace the windshield, let’s go over how a windshield is made and some of its basic properties.

How a windshield is made

Did you know that a windshield is designed to provide structural support for your vehicle? In the old days when cars were first manufactured they had no windshields, and instead drivers drove around with goggles to protect their eyes from wind and debris.  The windshield was invented in 1904 as obviously, driving around with goggles on was not only inconvenient, but could be dangerous, especially as cars became faster. Protecting passengers, as well as drivers became a priority.

But this took several tries. At first, windshields were made of plain, untreated glass that shattered on impact.  In these cases, it was probably better not to have a windshield than have one, as these sharp glass edges did much more damage than the benefit they provided. Injuries went up, and then manufacturers began using tempered glass. 

Tempered glass is very commonplace, and is a very simple and important technological innovation. Tempering is a special heat treatment that makes the glass stronger and resistant to shattering. This is the type of glass that you’ll have on your shower door. Now we use laminated glass, which is strong like tempered glass but also bends slightly on impact, and shatters even less.  Multi-layered laminated glass is considered the safest type of auto glass and is required by law. 

Modern windshields are generally made of treated glass that consists of a few layers.  Generally, two sheets of glass are used and a plastic layer is laminated between them for safety. 


Finished windshield glass Image from:

Windshield construction

Glass is composed of numerous oxides, when fused together upon heating, form glass.  They are silica, sodium oxide and calcium oxide.  The essential components are silica sand, soda ash and dolomite.  Small amounts of aluminum and potassium oxide are often added.  Quartz, a rock that you can easily find outdoors is composed primarily of silica. Silica is the main ingredient, making up 60-70% of the total. These ingredients are mixed together and heated at high temperature.

Glass needs to have a few important properties to make it safe and functional.  It needs to have clarity and to give the vehicle structural support to the roof in case of a roll over accident.  The glass also needs to be able to withstand damage during minor collisions and flying debris.  This is where lamination comes in.  A car windshield is actually made from three layers of glass as shown on the graphic.  The inner layer is a layer of plastic, poly-vinyl butyral between two layers of tempered glass.

Your windshield is made of three layers

So when a rock flies into your windshield, it only pierces the first layer of glass in this three-layer construction.  This limits the damage to the first layer of your windshield and still allows it to retain structural integrity and protects the occupants of the vehicle. By isolating the damage to the first layer of the windshield, you can fix this and avoid having to replace the entire windshield.

There are almost as many windshields as there are vehicles, since they all come in different sizes.  Due to design standards, larger windshields are becoming more and more popular.  This is due to their aerodynamic design which also allows for greater visibility and in turn, should increase safety on roads. 

Why does a chip turn into a crack? 

The reason a chip usually spreads to a crack is because water gets inside of it and expands.  Water is attracted and pulled in by surface tension.  If the rock pierces through the laminate layer, more moisture can delaminate the glass from the middle (plastic) layer.  This membrane will fog and cause a larger obstruction to vision.  Of course water can freeze in the chip, and it can carry dirt with it, and there is no way to remove it. 

This is why you should always try to repair every chip, every chip has the potential to become a nasty windshield crack.  Again, chip repair is recommended for certain types of stone damage.  Not all chips are the same, and typical stone damage repair is recommended for certain types only. 


This is a “flower” type crack and can be fixed. Image source: Alicja Gados

How to repair a chipped windshield

To repair a chipped windshield, you can either do it yourself or take it to a glass professional.  If you are doing it yourself you can either purchase a kit (about $10-15) or use crazy glue.

Do it Yourself Windshield repair

There are a number of windshield repair kits out there. The nice thing about these is they already contain everything you will need, including suction cups that seal in the crack. They are also very inexpensive. The best one we found was the Rain-X windshield repair kit which can fix a chip not more than an inch in diameter, and also cracks (as long as they are not longer than 12 inches). 


Most kits will fix these types of glass damage.  Image from

You can also fix it with a super glue and isopropyl alcohol.  You will need a hair dryer for this job. Let’s go over how to fix a chip, then a crack.

Fixing a chip

What you will need

  1. Super glue
  2. Isopropyl alcohol
  3. A hair dryer
  4. Scraper or razor blade

You might also want to stick a piece of paper on the inside of the window so you can see the crack better.

1. Make sure the windshield is dry

Start with a dry windshield that is about room temperature.  On a rainy or snowy day, keep your car inside until the windshield dries and warms up. You can further dry it with a hair dryer.  You can clean the crack or chip first, but make sure not to use window cleaner or detergents of any kind.  Acetone (nail polish remover) or lighter fluid will work, the main benefit being that it evaporates quickly.   But don’t use too much so that it will run down the glass as this can damage the paint on your car. 

2. Put a bit of alcohol in the chip

Spread the alcohol into the chip, then dry it out with a hair dryer. Put the hair dryer right in the crack for about 30 seconds to a minute.

3. Put a little bit of glue in the crack

Now, squeeze glue into the chip. Let it dry by waiting a few seconds. We suggest you also use a scraper to scrape some of the excess glue from the area when dry.

Of course, this method isn’t perfect and you may be able to still see it, however, it’s cheap and fast, and should keep the crack from spreading.

Fixing a crack

You can also fix a windshield crack.  For these, don’t try to do it with crazy glue but buy a kit. The most important thing to start with is to give the crack a place to stop.  Use a glass drill bit, and drill a hole to the end of the crack. This will keep the crack from spreading and you can start to fill it in from there. 

You can usually pick up one of these filler kits for around $15.  What you really need is to have one of these suction cups, which comes in the kit, and a plunger which really forces the resin in.

This is as close as possible to a professional repair. 

If you are fixing a crack, you can do it yourself with glue as described above or you can use a kit. You can easily get away with glue for a chip, but for a crack, you should buy one of these kits, like the one by Rain-X.

What you will need:

  1. The repair kit
  2. A glass drill bit
  3. Grease, chap stick or even Vaseline, to slide the suction cups along the crack
  4. Glass cleaner

1. Make sure the windshield is dry

Again, you should make sure your windshield is fully dry.

2. Stop the crack

You will need to stop the crack from spreading. Simply give the crack no place to spread by drilling in a small hole at each end with a glass drill bit.

3. Put grease on either side of the crack

Put the suction cup on the center of the crack, and see where the suction cups sit. Spread the grease over where the suction cups will slide.  This will make it easier and faster to fill the crack.


Spread grease on either side of the crack to guide the suction cups along it. Note the drill bit mark made on the end to keep the crack from spreading. Image from:


The suction cups will slid along the length of the crack making it much easier to fill. Image from:

 4. Put laminated sheets on top

Get the air bubbles out by putting the laminated sheets on top, and allow them to sit for a few hours. The resin will cure in the sun. 

5. Clean it up and scrape

Clean up the grease by using a cleaner. Then scrape off the excess glue with a razor blade.  The razor blade should be included with your kit.

This is surprising affective solution and is as close to a professional job as you can get.  Professional glass repair shops use a similar method, with a high end sliding suction cup-type tool that runs along the length of the chip or crack. 

Windshield replacement

If the damage on your windshield is too extensive, including multiple chips, the type of chips that can’t be filled, (such as ‘spider cracks’) long cracks spanning along the length of your windshield in several spots, it may be just easier and more straightforward, or even necessary to replace it.  A new windshield will cost you around $150-$300 and up.  It depends on the type of glass, type of vehicle and on the glass company you choose.

If you do need a new windshield, here is what you should do to get the best deal. Start by making a list of quotes, which can be easily obtained online.  Many companies want you to fill out a form after which they will phone you to give you a quote and try to book the service

Search glass companies

Start by doing an online search of glass shops in your area.  Check their customer ratings and select the ones with the best reputation and availability and turn around.  You can also get door to door service at some shops, they will pick up the car and drop it off with the new windshield. Of course this will cost you more.

Request a quote

In order to get a quote, you will have to fill out a form online. Prices will vary by quality of glass, brand, and type of glass.


 Select the one that fits your budget, service and type of glass requirements the best.


A crack can restrict visibility on the road. Image credit: Daimoneklund via Flickr.

We hope you found the article helpful in determining whether to fix or replace your windshield. Remember to take care of those cracks and chips, especially those that are in your line of vision. Stay safe out on there on the roads! 

For more reading check out:

Further Reading:

Popular Mechanics ‘Windshield Repair 101: How to fix your windshield’

Car Is your windshield repairable?

Made ‘Automobile Windshield’

RainX Repair Kit 

Windshield ‘The dangers of driving with a damaged windshield’